66 GMC Wouldn't turn off this morning?

[AndrewJoey]

The starter seemed really rough, then about 1 mile into my drive I felt vibration from the front, turned around and got home, but I smelled burningish, no smoke, not the coolent, I don't think. and when I tried to turn off the truck the ignition didn't work and it kept running. Still smelled like something was really hot. I disconnected the battery to turn off the engine.

351 V6 Magnum
1966 GMC 3/4 ton

Thanks for any advice guys!

Andy

[PGSigns]

Sounds like the starter may have been hung up. If the solenoid was still engaged it will be supplying voltage to the coil.
Jimmy

[AndrewJoey]

Originally Posted by PGSigns

Sounds like the starter may have been hung up. If the solenoid was still engaged it will be supplying voltage to the coil.
Jimmy

That makes sense, I think it needs a new starter and ignition. I don't even need a key to turn start. Thank you, that kind of confirms what I was thinking. Great place to start anyway.

[TJ's Chevy]

Had my GMC's starter rebuilt and it works fine. My issue was the solenoid would click. I'd start there for sure, also check the ignition switch..it could also have issues. By the way....Jealous you have a 351M. lol! I have a 305E in my 64. Hoping to put a 401 or 478 in there someday.

[AndrewJoey]

Originally Posted by TJ's Chevy

Had my GMC's starter rebuilt and it works fine. My issue was the solenoid would click. I'd start there for sure, also check the ignition switch..it could also have issues. By the way....Jealous you have a 351M. lol! I have a 305E in my 64. Hoping to put a 401 or 478 in there someday.

Thanks bro, so the 351M is good? I like it because I like stock, but it sure is a beast.

[AndrewJoey]

Originally Posted by PGSigns

Sounds like the starter may have been hung up. If the solenoid was still engaged it will be supplying voltage to the coil.
Jimmy

Would that mean that my coil is probably shot now since I could smell something burning? I'm guessing at this point I need a new solenoid, and probably another new coil since it is more than likely melted. I don't know if that's even possible.

[TJ's Chevy]

Oh yeah! 351M is a darn good motor. Lot's of torque. Your looking at a 4.56 bore and 3.58 stroke. You've got Real cylinders there. lol My 305 has a 4.25 bore and 3.58 stroke. And for your info, once you get the bugs worked out....tune it up, and do a 4 barrel intake mod. You have the magnum manifold so the mod is super easy. Something to consider if your interested. Also dual exhaust helps A Lot. Here's a picture of mine. My 305 runs a ton better than before, probably putting out over 320 torque. lol

[PGSigns]

I would pull and have the starter rebuilt. Start there. Hard to hurt a coil, the smell was your starter. You will need to see what is up with your ignition switch and associated wiring that may be what the root of the problem is.
Jimmy

[Brad54]

Could have also been the wiring harness burning, causing a short somewhere.
Connect the battery and see if you smell something burning again without the truck running.

Had the headlight switch internals come apart on my '61--one of the brass contacts inside the switch came out of the Bakelite, bounced around and laid over to other contacts, causing a short... the wires at the dimmer switch burned, which caused the TAIL LIGHTS to go out! I had headlights, and didn't know I had no tail lights until a very irate cop yelled at me for driving with my lights off.

I did have turn signals though, so I put on the right turn signal and continued on down the road with one tail light blinking until I got to the hotel.

It was fall, it was rainy, and the state I was driving through was an endless pile of burning leaves... and that's exactly what the burning wiring harness smelled like, too--burning leaves.

The wiring in our trucks is 50 years old. Something to keep in mind.

-Brad